drew.kay at gmail.com
Sun Jul 3 04:08:46 UTC 2011
>> Robert Heller suggested that UPS architecture matters:
>> AC->DC::DC Batteries::DC->AC
>> Where input AC is electrically decoupled from output AC.
>> Not many adverts for UPS's explain whether this is the case with their
> APC's SmartUPS line, Liebert, and Eaton Powerware are all true-sine wave UPS's, and do proper decoupling. Unfortunately, this kind
> of data doesn't make for great ad copy, so it's left out, and you have to dig deep into datasheets to get that information. I pretty
> much only use APC, and we have truly crap power here. Because of some heavy industry in the area, brownouts are common, and that'll
> kill a PC power supply better than anything. I've pulled one 7 year old APC from a server closet where the lightning took the top of
> the telephone pole OFF. THE UPS was fried, some of the breakers in the building were fused (!), but the servers were fine, outside
> of the router that got zapped from the DSL modem.
I beg to differ about APC. The accepted term for what Robert described
is a "double conversion" or "online" UPS. APC's SmartUPS family is
only available with the double conversion feature if you specify a
"SmartUPS Online" model. The rest of the SmartUPS family use "Line
Interactive" which runs on mains power until the
voltage/current/frequency goes out of tolerance, at which point they
cut over to battery. The Liebert GXT2/3 family which we use quite a
bit of were, until recently, strictly double conversion.
"This started out as a hobby and spun horribly out of control."
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